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Competency Area 5: Soil conservation AEM

PO 52. Understand the relation between tillage practices and:

  1. Residue cover
  2. Soil roughness
  3. Soil quality
  4. Residue fragility and persistence

Residue cover

Almost every tillage pass reduces residue cover. It is possible to estimate the effect of a tillage system on residue cover based on the percent cover after harvest, overwinter residue decomposition, and estimates of percent cover remaining after different tillage operations. Tables have been published in Midwest Plan Service – publication 45 (Conservation Tillage Systems and Management, 2nd Ed. , 2000), chapter 7).

Soil roughness

The soil surface can be smoothened by soil tillage. However, subsequent traffic creates more soil roughness after tillage, and the danger of rut formation is greater on a previously tilled soil than a long-term no-tillage soil. Ridge tillage leaves the soil in ridges.

Soil quality

Soil tillage degrades soil quality because of its negative effects on soil structure.

Residue fragility and persistence

Fragile and non-fragile residues are terms used to distinguish the different decomposition rates of crop residues. Fragile residue is from crops such as soybeans, canola, dry beans, and potatoes. Non-fragile residue is from crops such as corn, alfalfa, and small grains. The reduction in residue cover due to tillage is much greater in fragile residue than in non-fragile residue, and the persistence of fragile residue is less than that of non-fragile residue (see chapter 7 of MWPS, 2000).